말백합, Meretrix petechialis (Lamarck)의 난 발생에 미치는 수온, 염분, 수용밀도의 영향

This study was performed to describe the effect of water temperature, salinity and density on the eggs development of the hard clam, Meretrix petechialis. Eggs of Meretrix petechialis were turned out to be demersal isolated eggs of 82.3-86.1 μm in an average diameter after spawning. The hatching rate of D-shaped larvae by elapsed time after spawning was the highest in fertilization immediately after spawning and distinguished decrease from 1 hour of spawning. The optimum water temperature for development of D-shaped larvae from fertilization was ranged between 25℃ to 27℃. However, D-shaped larvae was not developed at 33℃ of water temperature. The required time from fertilization to D-shaped larvae were 37.3 hours in 20℃, 20.8 hours in 25℃, and 15.3 hours in 30℃. Biological minimum temperature for the egg development was estimated to be 12.4℃ in average. The range of salinity for the development of eggs were 20.0-37.5 psu, optimum range was estimated to be 27.5-32.5 psu.